Finally we would like to discuss the hypothetical possibility to accommodate the result of the present paper
on \(q_{44}\)  with the one in [1]}. In a later paper, [2]}, the authors
of [1]} claim to have still a missing term in Eq. (10.2) of [2]} on radiation reaction,
which is not yet quantified. It is of the type
\(\delta H_{\rm tail} = a \eta ^{10} \nu ^2 \frac{(p.n)^4}{r^4},\) 
